It is a fact well known in the art that a bioabsorbable material formed of a bioabsorbable polymer such as a polymer obtained by polymerizing lactide or by polymerizing lactide and caprolactone is used as a cell scaffold material in the field of regenerative therapy. Additionally, when bioabsorbable polymers are produced by polymerization, tin compounds excellent in catalytic activity such as tin octylate are often used as catalysts. It is to be noted that the afore-mentioned tin compound offers a problem of the toxicity to living organisms. For the purpose of solving this problem, there have been proposed the use of metal zinc lower in the toxicity to living organisms as compared to the aforementioned tin compound and the use of powdery metal zinc as the polymerization catalyst for the polymerization of lactide or caprolactone polymer which is a bioabsorbable polymer (Non-Patent Documents 1 and 2).    Non-Patent Document 1: Polymer International 46, 177 (1998)    Non-Patent Document 2: J Biomed Mater Res 69A, 417 (2004)